On Channel State Information in Multiple Antenna Block Fading Channels

Conference PaperMotivated by large capacity gains in multiple antenna systems when perfect channel state information is available at both receiver and transmitter, we examine the achievable rates of channel measurement based techniques. We assume that instantaneous channel state is not known a priori and measured at the receiver and transmitter using part of the total system resources. The receiver side information is obtained using a preamble. For transmitter side information, two classes of feedback channel are studied, a time-division duplex mode and a two-way channel mode. For each class, we study both low-rate quantized and reverse preamble feedback. Lower bounds for achievable rates are derived for the proposed methods, and these bounds are used for resource allocation among the preamble and the feedback. For slowly fading channels, significant gains over non-measurement schemes are possible even with a single bit of feedback.Noki